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R/E/P => Klaus Heyne's Mic Lab => Topic started by: J. Mike Perkins on June 21, 2013, 02:54:02 PM

Title: Neumann K870/K87/K67 Capsule Types Through The Years: How To Identify
Post by: J. Mike Perkins on June 21, 2013, 02:54:02 PM
Klaus:

I don't think this has been covered in any one post, but could you or someone here explain the different K870/K87/K67 types that Neumann has used over the years and about when did they make the changes?  I have seen brass metal ring K67 capsules on old U67 mics from the early 1960's.  I have a very old U87 that has a sort of rubberized fiber board like capsule ring.  I have another U87 from the 70's that has a brown plastic ring capsule.  I have a U77 that looks like it has a replacement K67 white plastic ring capsule from the 1980's or 90's(?).  So there appear to be at least 4 overall types?  Has the diaphragm material been the same over the years?  Is the difference in tone due just to the material that makes up the capsule ring or is there something else going on? Finally, I know the handwritten numbers on the capsule ring mean something and one of the numbers is some type of date code.  Can you explain that?  Thank you again for sharing your knowledge on this forum.
Title: Re: Neumann K870/K87/K67 Capsule Types over the years
Post by: klaus on June 21, 2013, 04:26:54 PM
Thanks for reminding me to do something I should have done a long time ago.

Here is a rough overview over the K67/87/870 capsule generations. One day, I will add photos, just not right this minute.

1. Similar appearance as K47/49, but with two backplates mounted against each other with four M3 screws (If I recall correctly). Brass diaphragm rings, no mounting threads for the capsule mount in the backplates (these were held in the threaded mounting ring via three pointed set screws), ca. 1960-1961

2. Same as above, but with eight M2 threads in the two backplate halves (2x4, offset from each other), ca. 1961 to 1964

3. Same as above, but with brown fiberboard diaphragm rings replacing the brass rings, ca. 1964 to 1966

4. First generation of plastic diaphragm rings (ivory color), whose mounting screws were recessed into the plastic, to be flush with the ring's surface, ca. 1966 to 1980

5. Same as above, but with white instead of ivory-colored rings

6. Same as above, but diaphragm mounting ring screws no longer recessed, since 1980

Versions five and six went through five generations combined; their subtle differences through time are only noticeable to an expert. Likewise, it's initially not easy to separate a K67 from a K87 by looking at it. Though, upon closer inspection, you can see the 40µ aluminum separator ring between the two backplate halves on K67/870.

Since the late 1970s, all K67/87/870 are marked with a single digit indicating the last digit of the year of manufacture (i.e. "7" for 1987, 1997, 2007, etc.)  This can be confusing for a layperson, because numbers repeat every 10 years. But the combination of build characteristics and date number allows pinpointing the year of manufacture fairly easily.

P.S.: Because of considerable interest, I also made this post a sticky
Title: Re: Neumann K870/K87/K67 Capsule Types Through The Years: How To Identify
Post by: gkippola on June 23, 2013, 02:28:53 PM
Anyone know the approx years that Telefunken logoed 67s were shipped?
Title: Re: Neumann K870/K87/K67 Capsule Types Through The Years: How To Identify
Post by: klaus on June 23, 2013, 09:06:15 PM
They were"loggoed" from the beginning to the end to any Telefunken-distributed dealer/consumer
Title: Re: Neumann K870/K87/K67 Capsule Types Through The Years: How To Identify
Post by: Marnay on July 05, 2013, 11:19:28 AM
Hello Klaus,
As you had indicated it is difficult to find the difference between a K87 and K870 capsule.
Can you help me with it's pictures of indicate me the K870 K87?
The B capsule is covered with plastic all around.

Thanks in advance
Title: Re: Neumann K870/K87/K67 Capsule Types Through The Years: How To Identify
Post by: klaus on July 05, 2013, 01:55:12 PM
The "A" capsule seems to be a K67/870, deducting from the sliver-appearing small spacer between the halves.

The "A" capsule may be a K87, if I interpret the small nick in the plastic ("TE46" side) under the 9:30 screw correctly: this would be where the lead-out solder eyelet for the front diaphragm wire is mounted. The screw indents the plastic a bit, because it's pressing down into the eyelet at that spot. Only (older) K87 have that eyelet.
Title: Re: Neumann K870/K87/K67 Capsule Types Through The Years: How To Identify
Post by: Marnay on July 05, 2013, 02:31:10 PM
Thanks Klaus
You confirmed this as I thought, A capsule is a K870/67 it has a silver leaf between the halves
And not the other capsule.
Title: Re: Neumann K870/K87/K67 Capsule Types Through The Years: How To Identify
Post by: M Stage on December 12, 2014, 04:18:09 AM
This thread seemed an appropriate one to ask the question of whether or not the attached photos are of an authentic K870 capsule. The capsule is from a mid 1990s u87ai.  Is it an authentic Neumann capsule? It does not have the hand written numbers that most I have seen have. Also it is missing the white curved plastic on top. Any thoughts on this one? Has it been reskinned? Why would it be missing the numbers seen on most others?
Title: Re: Neumann K870/K87/K67 Capsule Types Through The Years: How To Identify
Post by: M Stage on December 12, 2014, 04:20:51 AM
and the rear view of the capsule
Title: Re: Neumann K870/K87/K67 Capsule Types Through The Years: How To Identify
Post by: M Stage on December 12, 2014, 02:44:21 PM
Any thoughts or info from anyone on this capsule pics I have posted?
Title: Re: Neumann K870/K87/K67 Capsule Types Through The Years: How To Identify
Post by: klaus on December 12, 2014, 04:07:44 PM
To give a conclusive answer, I need one more close-up: a head-on shot of the area of the white plastic diaphragm ring that shows the big hole (there are two of them on each side, which are the opposite ends of the four attachment screws for the capsule halves).

To be more precise: the location of the holes on the front side would be at 6:30 and 12:30 respectively.
Title: Re: Neumann K870/K87/K67 Capsule Types Through The Years: How To Identify
Post by: M Stage on December 12, 2014, 04:28:01 PM
Here is the front of the k870 capsule in question.
Title: Re: Neumann K870/K87/K67 Capsule Types Through The Years: How To Identify
Post by: klaus on December 12, 2014, 06:44:16 PM
I have a pretty extensive collection of mid-1990s K87/870 which I compared yours to
They all had the black felt-pen i.d. markings which yours is missing. (Look carefully: can you still see their faint outline in the plastic?)

The other important difference: the lacquer seals on the 12 mounting screws on the diaphragm rings are missing. on your capsule. So, while I think the hardware on this capsule is genuine Neumann, down to the diaphragm ring injection mold indentations, their size and location, I believe that this capsule has been re-diaphragmed by a third-party provider.

Title: Re: Neumann K870/K87/K67 Capsule Types Through The Years: How To Identify
Post by: M Stage on December 12, 2014, 07:03:31 PM
May I ask how does re-diaphragming a capsule affect it's value compared with one that is original? What is a used all original Neumann k870 capsule valued at, and how much less is a re-diaphragmed Neumann k870 valued at?
Title: Re: Neumann K870/K87/K67 Capsule Types Through The Years: How To Identify
Post by: klaus on December 12, 2014, 07:13:55 PM
I have never found a case, where a re-diaphragmed capsule of a valuable condenser mic did not affect its value. \

Value reduction of a mic due to re-diaphragming can be dramatic (ELA M251) to barely noticeable (KM54). But this much has been clear to me, and I continue to stress it: I have yet to hear a re-diaphragmed K87 that sounds remotely as emotionally appealing, as smooth, as musical, as frequency balanced, as an original.

Most of the reskins of this capsule model I have heard are amateurishly made, and atrocious sounding, with many also suffering mechanical instability over time. And ALL reskins fall short enough, in my opinion, that I would never consider this cause of action, just because I could save a couple of hundred dollars on a reskin, and especially when the original capsule is still in production.
Title: Re: Neumann K870/K87/K67 Capsule Types Through The Years: How To Identify
Post by: M Stage on December 13, 2014, 01:23:36 PM
Thanks Klaus for the information. What would the value of a re-diaphragmed (or "reskinned" as it is also often called) k870 capsule be versus an original that has not been re-diaphargmed? I believe this is important to know and quantify as there are so many u87 microphones out there that have a "reskinned" (or rediaphragmed capsule) and the value of those, or how much it devalues the microphone as a whole, is not often written about anywhere I could find on the internet. And therefore new buyers are often ripped off by these "reskinned" capsules because sellers will often say they are just as good, when they often sound nothing like what they were before the re-diaphragming process.
Title: Re: Neumann K870/K87/K67 Capsule Types Through The Years: How To Identify
Post by: klaus on December 13, 2014, 03:01:38 PM
This is a highly subjective matter. I personally would discount the value of the mic to what it would cost me to restore it to the original capsule plus the sale of the fake one:

let's say, someone wants $3000 for a 'vintage' U87i whose capsule has been reskinned.
In this example, I would pay $2500 or thereabout, which would be the price for a new or used K87 ($650.- for a new one, anywhere from $400 to $800 for a used one- though I hate to quote prices that may be totally off base) I would also make a small allowance for selling the fake one on eBay (with full disclosure, of course), so I end up with the aforementioned $500 out of pocket which I need to recoup through the lowered purchase price of the mic. Granted, this is a lot of work to get  back to something that should have been there in the first place, but if the mic is really clean otherwise, it may be worth it.

And, before you ask the next inevitable question: how does a replacement Neumann K87 capsule affect the value of a 'vintage' U87? I have found, it does not affect it much, due to the fact that, with the exception of a short period of a few years in the early 2000s, the build and sound quality of K87s has stayed remarkably constant.
Title: Re: Neumann K870/K87/K67 Capsule Types Through The Years: How To Identify
Post by: anders on November 05, 2015, 09:42:05 AM
Hello.
I think this is the original capsule from my 1969 U87 (s.nr. 11962) originating from the Swedish National Radio. Does the look & numbers FG52/FG58 indicate a late 60`s K87 capsule?
The company supplying these mics routinely replaced the old capsules with NOS Neumann K87 capsules. I think they got a large batch from a defunct supplier/agent, or maybe a national broadcaster´s workshop department.
Thanks & Regards from Anders, Oslo-Norway
Title: Re: Neumann K870/K87/K67 Capsule Types Through The Years: How To Identify
Post by: klaus on November 05, 2015, 12:51:48 PM
Yes, the capsule shown is an original K87 from mid to late 1960s (K67 from that period looked the same).Similar capsule types with fiberboard surrounds were also issued for M49 and as replacement capsules forU47/48 during that period as K47/49.

This capsule type replaced the brass-ring type which was used in most U67 and M269 through 1965/66. No U87 exists, to my knowledge, with brass ring capsules. (U87 first appeared in 1967).
Title: Re: Neumann K870/K87/K67 Capsule Types Through The Years: How To Identify
Post by: anders on November 05, 2015, 02:59:27 PM
Thanks a lot, Klaus.
Some day I will put the original capsule back in to check if it still sounds and work decent :-)
Have you any idea which number is the "front" diaphragm, or are they the same?
Anders
Title: Re: Neumann K870/K87/K67 Capsule Types Through The Years: How To Identify
Post by: klaus on November 05, 2015, 04:00:13 PM
Neumann' capsule tolerances are tight enough that either side can be used as front.

However, within that tolerance, timbre differences can be large enough that I always find it worthwhile to do a "frontside selection" - placing the subjectively better sounding side to the front.
Title: Re: Neumann K870/K87/K67 Capsule Types Through The Years: How To Identify
Post by: AusTex64 on November 05, 2015, 11:51:36 PM
Klaus, how exactly do you do the test to select which side is the front? Do you use figure 8 and reverse phase on the mc pre for the back side, or do you disconnect each side and listen to only one half of the capsule at a time? Thank you.
Title: Re: Neumann K870/K87/K67 Capsule Types Through The Years: How To Identify
Post by: klaus on November 06, 2015, 12:40:27 PM
The latter. Testing capsule sides in figure-eight is only useful to detect gross performance errors. A proper front-side selection takes the extra work of disconnecting lead-out wires from the capsule, reversing its position on the capsule mount, reconnecting the wires, and listening again.

I then repeat the process on both sides again, to be sure of my judgement, because audible memory of timbral differences is very short.
Title: Re: Neumann K870/K87/K67 Capsule Types Through The Years: How To Identify
Post by: Piedpiper on November 06, 2015, 04:51:45 PM
Am I missing something or couldn't you just record each side and compare after the fact?
Title: Re: Neumann K870/K87/K67 Capsule Types Through The Years: How To Identify
Post by: klaus on November 06, 2015, 05:01:56 PM
Of course, you could record. But all recording is lossy. If you want to detect the more subtle differences between sides, nothing beats live testing.

I also forgot to mention that cardioid sounds different than figure eight on the same side. Another reason to switch the capsule around for testing.
Title: Re: Neumann K870/K87/K67 Capsule Types Through The Years: How To Identify
Post by: AusTex64 on November 06, 2015, 11:00:45 PM
The latter. Testing capsule sides in figure-eight is only useful to detect gross performance errors. A proper front-side selection takes the extra work of disconnecting lead-out wires from the capsule, reversing its position on the capsule mount, reconnecting the wires, and listening again.

I then repeat the process on both sides again, to be sure of my judgement, because audible memory of timbral differences is very short.

Thank you for the reply and sharing your experience. You are a very thorough dude! Now I have to go back to my U47 and C12 mic builds and do this test!

Regarding the question about recording mic tests, I have a ProTools test file where I use the same mic pre, matched gain and record the same dialog on a bunch of mics I've built and modified. Though you're correct about recording being lossy, that's what I do with my mics (record, not used in live performance). It's really interesting and informative to me to hear the differences in many different mics in a relatively controlled test.
Title: Re: Neumann K870/K87/K67 Capsule Types Through The Years: How To Identify
Post by: klaus on November 07, 2015, 02:22:21 AM
That will be the engraving on my grave stone:

"Here Rests A Thorough Dude"

Maybe you misunderstood my point. I am using live comparison tests, not because the mics are ever used for live  performance (which studio condensers are?), but I find an extra layer of revelation will be available when no AD/DA conversion and its associated signal path is employed. A good pair of headphones with minimal mic processing will do the trick. Try it some time!



Title: Re: Neumann K870/K87/K67 Capsule Types over the years
Post by: ryankalkman on August 21, 2016, 09:32:51 AM
I have what i thought was a K870/K67 capsule (the case is labeled that way), however since it has ivory rings, recessed mounting screw holes and the number 8 written on, I'm now lead to believe this is a 1978 capsule? in which case it must be a K87 since I assume the K870 only came into production in 1986 with the U87Ai?

Any help on this would be much appreciated ;)
   
Title: Re: Neumann K870/K87/K67 Capsule Types Through The Years: How To Identify
Post by: klaus on August 21, 2016, 01:00:37 PM
Pictures of your capsule show a 1988 K870. It does have white, not ivory-colored diaphragm rings. U87Ai were introduced in 1986, so this capsule fits into the timeline of the model.

But even before the introduction of the U87Ai, K67 capsules (now called K870 when designated for use in U87Ai) were continuously manufactured and sold as spare parts for the SM69fet mic (one version is still made today), and historic U67, M269 and SM69 tube mic models.

Neumann is one of the few legacy manufacturers which still makes and stocks spare capsules for most of its discontinued models.
Title: Re: Neumann K870/K87/K67 Capsule Types Through The Years: How To Identify
Post by: ryankalkman on August 22, 2016, 05:47:45 AM
thankyou klaus!
Title: Re: Neumann K870/K87/K67 Capsule Types Through The Years: How To Identify
Post by: Avgatzeblouz on August 24, 2016, 11:15:49 AM
I remember reading on a Neumann forum someone from the company stating these 3 capsules were sonically identical, the only difference being electric. Could that be true ?
Title: Re: Neumann K870/K87/K67 Capsule Types Through The Years: How To Identify
Post by: klaus on August 24, 2016, 12:53:22 PM
Two versions of the acoustically identical capsule, first introduced in the U67 in 1960, exist:

K67/870: no electrical separation between the two backplates. Figure-eight pattern is achieved by doubling the voltage to the rear diaphragm.

K87: electrical separation of the backplates, whereby figure-eight pattern is achieved by only energizing the rear diaphragm, not the rear backplate.

In theory, all K67/87/870 should sound identical because their physical dimensions and operating principle are the same. In practice these double-backplate capsules can vary greatly:

1. Polarization voltage of 47VDC (U87) causes a different electrostatic behavior of the membranes than pulling them with 60VDC (U87Ai, U67)

2. Subtle and not so subtle material and production changes through the years and versions of these capsules cause audible differences (read past threads about this).

3. Even performance differences of same era, same version capsules can be quite large, due to the handmade manufacturing process Neumann uses: build-specifications allow a maximum tolerance, capsule-to-capsule, of 4dB across the frequency spectrum (±2dB @1kHz).
Title: Re: Neumann K870/K87/K67 Capsule Types Through The Years: How To Identify
Post by: Avgatzeblouz on August 24, 2016, 03:28:05 PM
Hi Klaus, and thank you for sharing again your great knowledge. I'm in the process of building a pair of vintage U87 "clones", and contacted sennheiser Canada : a K87 is 1400 $ CAD !!!!! Can I use a K67 instead, or would it require too much a change in the circuit, making it therefore more a degradation than a benefit ?

Thanks again.
Title: Re: Neumann K870/K87/K67 Capsule Types Through The Years: How To Identify
Post by: klaus on August 24, 2016, 07:28:08 PM
The price seems high. U.S, prices are currently at or below $800.-

Yes, you can use a K87 instead of a K67. All you need to do is connect the two backplates.
You can do that by either stripping off the insulation sleeve off one of the four screws which hold the two capsule halved together, or you can simply bridge the backplates with a bare wire held down by screwing a couple of screws into two adjacent backplate threads- one in each backplate half.
Title: Re: Neumann K870/K87/K67 Capsule Types Through The Years: How To Identify
Post by: Avgatzeblouz on August 25, 2016, 11:00:50 AM
Hi Klaus, just to make sure, did you mix it up while typing ? My question was about using a K67 instead of a K87 in a 87 circuit, not the other way around.
Title: Re: Neumann K870/K87/K67 Capsule Types Through The Years: How To Identify
Post by: klaus on August 25, 2016, 11:20:47 AM
Oops, as you Americans would say...

Yes, I described the reverse scenario from yours, which unfortunately does not offer an easy solution: adding a 6µ insulation spacer and four insulation sleeves for the screws is not possible, unless you had these parts left over from a decommissioned K87.
Title: Re: Neumann K870/K87/K67 Capsule Types Through The Years: How To Identify
Post by: Avgatzeblouz on August 25, 2016, 11:25:01 AM
Thanks a lot, you are a great help, as always.
Title: Re: Neumann K870/K87/K67 Capsule Types Through The Years: How To Identify
Post by: Derek Samuel Reese on April 25, 2020, 09:25:30 AM
Old thread I know, but something came to mind..
If you have a healthy 1963 original k67 capsule and a healthy 1973 original k67 capsule  will they sound different from each other ?
Will there be a quality difference or any kind of difference?
I realize that no two u67’s sound the same even when they are both from the same period so did I answer my own question perhaps ?
Title: Re: Neumann K870/K87/K67 Capsule Types Through The Years: How To Identify
Post by: klaus on April 25, 2020, 02:51:38 PM
You can safely assume that, originally in 1973, a 1973 K67 will sound exactly like a K87 would have sounded of that same build era. But time may have done all kinds of numbers on diaphragms and other parts of the mic, (contrary to speculation, diaphragm tension is not among them).

So, you are right, it's hard to get a baseline. But this much is clear: During both eras-the early 1960s, and early 1970s- Neumann produced large diaphragm capsules that had exceptionally good, mediocre, and a few not so good quality (that is on the highly elevated scale of Neumann's quality control!)
Title: Re: Neumann K870/K87/K67 Capsule Types Through The Years: How To Identify
Post by: gtoledo3 on April 25, 2020, 03:20:34 PM
You can safely assume that, originally in 1973, a 1973 K67 will sound exactly like a K87 would have sounded of that same build era. But time may have done all kinds of numbers on diaphragms and other parts of the mic, (contrary to speculation, diaphragm tension is not among them).

So, you are right, it's hard to get a baseline. But this much is clear: During both eras-the early 1960s, and early 1970s- Neumann produced large diaphragm capsules that had exceptionally good, mediocre, and a few not so good quality (that is on the highly elevated scale of Neumann's quality control!)

Klaus, are you asserting that capsule manufacturers who indicate that tension loss happens over time, or people who send in mics to be serviced because of the diaphragm losing tension, are simply all incorrect? Interesting hill to stand on. Does it continue to be speculation if it has been measured? It may also be worth remembering that not everyone exerts the caution you advise in mic placement on loud sources or general care. I have no doubt many well cared for specimens should not exhibit much if any perceivable change, but then again this is a forum that seems to flesh out the finest, smallest possible differences in performance of audio equipment.
Title: Re: Neumann K870/K87/K67 Capsule Types Through The Years: How To Identify
Post by: Derek Samuel Reese on April 25, 2020, 03:34:50 PM
You can safely assume that, originally in 1973, a 1973 K67 will sound exactly like a K87 would have sounded of that same build era. But time may have done all kinds of numbers on diaphragms and other parts of the mic, (contrary to speculation, diaphragm tension is not among them).

So, you are right, it's hard to get a baseline. But this much is clear: During both eras-the early 1960s, and early 1970s- Neumann produced large diaphragm capsules that had exceptionally good, mediocre, and a few not so good quality (that is on the highly elevated scale of Neumann's quality control!)
Wow, ok well this is where my brain is going, You repaired and cleaned up my 1978 capsule and brought back to life the sound i heard before sending it to another tech who was incompetent.
I consider myself extremely fortunate to have made your acquaintance and i was blessed to have you work on my 1963 U67.
The moment my microphone came back it sounded like magic all over agin, sensual and robust.
So i ask a ton of question because i am very curious but i am really content when i pull up a chair to record my acoustic guitar or when i sing my little heart out.
Again i take the time to tip my hat to you Klaus because your brilliance brought me to tears when i heard my microphone.
Title: Re: Neumann K870/K87/K67 Capsule Types Through The Years: How To Identify
Post by: gtoledo3 on April 25, 2020, 04:09:42 PM
After seeing the very laudatory post - I feel I should add....I also feel Klaus has a depth of knowledge about microphones that is second to none, and has done work that has captivating sonic results.

My scrutiny of fine points of mic technology is only out of a love for the field and the continued pursuit of greater knowledge. Ultimately, sometimes even experts come to disagreement through unrecognized differences in context or more subjective factors.
Title: Re: Neumann K870/K87/K67 Capsule Types Through The Years: How To Identify
Post by: afterlifestudios on April 25, 2020, 07:28:37 PM
Seeing this thread made me want to take a peek at my “pair” of old (non “a”) U87’s capsules.
One head assembly has the “kk 87 a” badge with serial number as expected, and the capsule looks good.  The other U87 has no badge on the head assembly, but a serial number baked into the plastic.  It also has epoxy over one of the fastening screw holes, leading me to believe it’s never been opened.  Not feeling like I should open it just out of curiosity?  (It sounds great!).
Any info to be learned from what’s visible?

Title: Re: Neumann K870/K87/K67 Capsule Types Through The Years: How To Identify
Post by: klaus on April 25, 2020, 08:27:49 PM
The blue seal over one of the mounting screws on the clear plastic switch assembly is not a Neumann seal, but possibly one of mine, which I attach as condition of my warranty. 
The white head is possibly from a late 1970s U87, judging from its serial number. The "A" in the serial number is not related to the U87A.
Title: Re: Neumann K870/K87/K67 Capsule Types Through The Years: How To Identify
Post by: afterlifestudios on April 26, 2020, 01:20:47 AM
Thank you Klaus.  I always favoured that u87 slightly over the other.  Perhaps it was because of your handiwork on the capsule. (Likely a cleaning?)
The one slightly strange thing to me is that the serial number on the non-white head and body is lower (older) but it has the baby blue 50 Ohm impedance dot on it.  The one with the late 70’s white head has the red 50 Ohm dot.  Does that make chronological sense?
Title: Re: Neumann K870/K87/K67 Capsule Types Through The Years: How To Identify
Post by: klaus on April 26, 2020, 11:18:33 AM
No, it does not make sense. A red dot next to the serial number identified the padded U87 version until the early 1970s, thereafter the dot was changed to light blue. (I'd call it turquoise)
Title: Re: Neumann K870/K87/K67 Capsule Types Through The Years: How To Identify
Post by: afterlifestudios on April 26, 2020, 11:49:33 AM
Thanks Klaus. Yes, it seemed out of sequence to me too.  Yet, here they are.   (It may be the same color/lacquer that was used on the mounting screw on the switch assembly from previous post.)
Lower serial mic with “turquoise” dot. (930-20 circuit)
Higher serial mic with red dot. (930-21 circuit)
Title: Re: Neumann K870/K87/K67 Capsule Types Through The Years: How To Identify
Post by: klaus on April 26, 2020, 02:25:02 PM
The blue dot does not look stock. Sloppy paintwork is not a hallmark of Neumann, also, the color is not right.
Title: Re: Neumann K870/K87/K67 Capsule Types Through The Years: How To Identify
Post by: afterlifestudios on April 26, 2020, 02:41:28 PM
Thank you Klaus.  Agreed.  Sloppy paintwork is not a hallmark of yours either, but would this (like the mounting screw paint on the switch assembly) be something you may have done after working on it? Maybe impedance strapping change?
Title: Re: Neumann K870/K87/K67 Capsule Types Through The Years: How To Identify
Post by: Derek Samuel Reese on April 26, 2020, 02:54:37 PM
Seeing this thread made me want to take a peek at my “pair” of old (non “a”) U87’s capsules.
One head assembly has the “kk 87 a” badge with serial number as expected, and the capsule looks good.  The other U87 has no badge on the head assembly, but a serial number baked into the plastic.  It also has epoxy over one of the fastening screw holes, leading me to believe it’s never been opened.  Not feeling like I should open it just out of curiosity?  (It sounds great!).
Any info to be learned from what’s visible?
What does these numbers represent ? i zoomed in but can't read the numbers ?
Im assuming these are the baked in the plastic numbers you mentioned ?
I also have a series of numbers on my u67 in the same place.
Title: Re: Neumann K870/K87/K67 Capsule Types Through The Years: How To Identify
Post by: afterlifestudios on April 26, 2020, 03:01:31 PM
What does these numbers represent ? i zoomed in but can't read the numbers ?
Im assuming these are the baked in the plastic numbers you mentioned ?
I also have a series of numbers on my u67 in the same place.

This is the serial number of head assembly I believe.  Later moved to a badge like in the other photo.  (Klaus please correct me if wrong?)
Title: Re: Neumann K870/K87/K67 Capsule Types Through The Years: How To Identify
Post by: Derek Samuel Reese on April 26, 2020, 03:07:07 PM
so a serial number of the head assembly doesn't have anything to do with the serial number on the bottom of the mic ? Then there must be another group of numbers somewhere that can date the head assembly ?
That would be cool.
Title: Re: Neumann K870/K87/K67 Capsule Types Through The Years: How To Identify
Post by: afterlifestudios on April 26, 2020, 03:12:36 PM
so a serial number of the head assembly doesn't have anything to do with the serial number on the bottom of the mic ? Then there must be another group of numbers somewhere that can date the head assembly ?
That would be cool.

Again, Klaus will be able to verify, but in my efforts to date mics with Neumann, they replied that they have no dates for serials of heads.  Only for "bodies".
Title: Re: Neumann K870/K87/K67 Capsule Types Through The Years: How To Identify
Post by: Derek Samuel Reese on April 26, 2020, 03:19:40 PM
Again, Klaus will be able to verify, but in my efforts to date mics with Neumann, they replied that they have no dates for serials of heads.  Only for "bodies".
This is interesting, why even put numbers on something if a record won't be kept.
I also wondered about the serial number on my psu ?
it happens to be a lower number than on my u67, but if the mic's serial number has nothing to do with the psu serial number than we will never know lol
im gonna go have a bowl of cereal now.
Title: Re: Neumann K870/K87/K67 Capsule Types Through The Years: How To Identify
Post by: klaus on April 26, 2020, 05:12:14 PM
Numbering mics, power supply and other relevant parts like head assemblies is done to:

1. record design changes and when they happened, which will also be noted on internal schematics (note in most schematics it will say "starting with serial number XXXX" or a letter suffix indicating major changes in heads)

2. to trace sales and connect each to a specific item- when it was sold, and where it went, and how much it sold for

Neumann's power supply numbers are usually higher than the corresponding mics they came with: spare units, loss, theft, damage, raised the numbers. It is very rare to have a number match between mic and p.s.
Title: Re: Neumann K870/K87/K67 Capsule Types Through The Years: How To Identify
Post by: David Satz on April 26, 2020, 05:15:17 PM
There's always some detailed information that gets generated during production as a microphone manufacturer measures and tracks the characteristics of "sensitive" components, e.g. sorting a large batch of semiconductors or capacitors according to their exact, measured values into some number of bins. But by the time assembly and testing are complete, the characteristics of those components have been adequately balanced by other interrelated selections.

There's no necessary reason for a manufacturer to code such parts in a way that's transparent to the general public, or even to archive that information for themselves in many cases. Eventually such information loses its reliability anyway as those components age, or because of repairs that the factory knows nothing about.

Some people even choose to modify their microphones, or so I've heard; that may be fake news, though ...

--best regards
Title: Re: Neumann K870/K87/K67 Capsule Types Through The Years: How To Identify
Post by: klaus on April 26, 2020, 05:19:25 PM
Completely fake news.
Title: Re: Neumann K870/K87/K67 Capsule Types Through The Years: How To Identify
Post by: afterlifestudios on April 27, 2020, 05:37:54 PM
Is it known when the first non “dome shaped” base for the k67/870 capsule was introduced?  (The flat-topped one sits 6mm higher.)
.
Title: Re: Neumann K870/K87/K67 Capsule Types Through The Years: How To Identify
Post by: gtoledo3 on April 28, 2020, 04:10:51 PM
You can safely assume that, originally in 1973, a 1973 K67 will sound exactly like a K87 would have sounded of that same build era. But time may have done all kinds of numbers on diaphragms and other parts of the mic, (contrary to speculation, diaphragm tension is not among them).


Klaus, interestingly, in this thread you explain how you find capsules losing tension over time:

“Exactly what wears out?

Diaphragm tension becomes lower, affecting the diaphragm’s
uniformity of movement...”

Anyway, in this thread you also state that Neumann denies that, but fwiw, Neumann had and has stated that is a service issue, outside of whatever max SPL handling is.

http://forums.musicplayer.com/ubbthreads.php/topics/476943/question-for-klaus#Post476943

It’s certainly everyone’s prerogative to be able to change their mind, it just seems that the Klaus of yesteryear comes closer to agreeing with me than the current model. :-) Hope you’re having a good day!
Title: Re: Neumann K870/K87/K67 Capsule Types Through The Years: How To Identify
Post by: Derek Samuel Reese on January 21, 2021, 09:30:23 AM
I would love to know what the two letters and two numbers represent on an original u67 brass capsule ?
maybe the letters were the initials of the person testing the capsule ? but the numbers ? I'm just guessing lol
I realize that the brass capsule's were produced from 1961-1964 but I kinds of stinks that you don't know if you bought a 1961 or 1963 brass capsule, so each capsule is within a four year mystery ?